| K55 | Vascular disorders of intestine |
| K55.0 | Acute vascular disorders of intestine |
| K55.1 | Chronic vascular disorders of intestine |
| K55.2 | Angiodysplasia of colon |
| K55.20 | Angiodysplasia of colon without hemorrhage |
| K55.21 | Angiodysplasia of colon with hemorrhage |
| K55.8 | Other vascular disorders of intestine |
| K55.9 | Vascular disorder of intestine, unspecified |
| K56 | Paralytic ileus and intestinal obstruction without hernia |
| K56.0 | Paralytic ileus |
| K56.1 | Intussusception |
| K56.2 | Volvulus |
| K56.3 | Gallstone ileus |
| K56.4 | Other impaction of intestine |
| K56.41 | Fecal impaction |
| K56.49 | Other impaction of intestine |
| K56.5 | Intestinal adhesions [bands] with obstruction (postprocedural) (postinfection) |
| K56.6 | Other and unspecified intestinal obstruction |
| K56.60 | Unspecified intestinal obstruction |
| K56.69 | Other intestinal obstruction |
| K56.7 | Ileus, unspecified |
| K57 | Diverticular disease of intestine |
| K57.0 | Diverticulitis of small intestine with perforation and abscess |
| K57.00 | Diverticulitis of small intestine with perforation and abscess without bleeding |
| K57.01 | Diverticulitis of small intestine with perforation and abscess with bleeding |
| K57.1 | Diverticular disease of small intestine without perforation or abscess |
| K57.10 | Diverticulosis of small intestine without perforation or abscess without bleeding |
| K57.11 | Diverticulosis of small intestine without perforation or abscess with bleeding |
| K57.12 | Diverticulitis of small intestine without perforation or abscess without bleeding |
| K57.13 | Diverticulitis of small intestine without perforation or abscess with bleeding |
| K57.2 | Diverticulitis of large intestine with perforation and abscess |
| K57.20 | Diverticulitis of large intestine with perforation and abscess without bleeding |
| K57.21 | Diverticulitis of large intestine with perforation and abscess with bleeding |
| K57.3 | Diverticular disease of large intestine without perforation or abscess |
| K57.30 | Diverticulosis of large intestine without perforation or abscess without bleeding |
| K57.31 | Diverticulosis of large intestine without perforation or abscess with bleeding |
| K57.32 | Diverticulitis of large intestine without perforation or abscess without bleeding |
| K57.33 | Diverticulitis of large intestine without perforation or abscess with bleeding |
| K57.4 | Diverticulitis of both small and large intestine with perforation and abscess |
| K57.40 | Diverticulitis of both small and large intestine with perforation and abscess without bleeding |
| K57.41 | Diverticulitis of both small and large intestine with perforation and abscess with bleeding |
| K57.5 | Diverticular disease of both small and large intestine without perforation or abscess |
| K57.50 | Diverticulosis of both small and large intestine without perforation or abscess without bleeding |
| K57.51 | Diverticulosis of both small and large intestine without perforation or abscess with bleeding |
| K57.52 | Diverticulitis of both small and large intestine without perforation or abscess without bleeding |
| K57.53 | Diverticulitis of both small and large intestine without perforation or abscess with bleeding |
| K57.8 | Diverticulitis of intestine, part unspecified, with perforation and abscess |
| K57.80 | Diverticulitis of intestine, part unspecified, with perforation and abscess without bleeding |
| K57.81 | Diverticulitis of intestine, part unspecified, with perforation and abscess with bleeding |
| K57.9 | Diverticular disease of intestine, part unspecified, without perforation or abscess |
| K57.90 | Diverticulosis of intestine, part unspecified, without perforation or abscess without bleeding |
| K57.91 | Diverticulosis of intestine, part unspecified, without perforation or abscess with bleeding |
| K57.92 | Diverticulitis of intestine, part unspecified, without perforation or abscess without bleeding |
| K57.93 | Diverticulitis of intestine, part unspecified, without perforation or abscess with bleeding |
| K58 | Irritable bowel syndrome |
| K58.0 | Irritable bowel syndrome with diarrhea |
| K58.9 | Irritable bowel syndrome without diarrhea |
| K59 | Other functional intestinal disorders |
| K59.0 | Constipation |
| K59.00 | Constipation, unspecified |
| K59.01 | Slow transit constipation |
| K59.02 | Outlet dysfunction constipation |
| K59.09 | Other constipation |
| K59.1 | Functional diarrhea |
| K59.2 | Neurogenic bowel, not elsewhere classified |
| K59.3 | Megacolon, not elsewhere classified |
| K59.4 | Anal spasm |
| K59.8 | Other specified functional intestinal disorders |
| K59.9 | Functional intestinal disorder, unspecified |
| K60 | Fissure and fistula of anal and rectal regions |
| K60.0 | Acute anal fissure |
| K60.1 | Chronic anal fissure |
| K60.2 | Anal fissure, unspecified |
| K60.3 | Anal fistula |
| K60.4 | Rectal fistula |
| K60.5 | Anorectal fistula |
| K61 | Abscess of anal and rectal regions |
| K61.0 | Anal abscess |
| K61.1 | Rectal abscess |
| K61.2 | Anorectal abscess |
| K61.3 | Ischiorectal abscess |
| K61.4 | Intrasphincteric abscess |
| K62 | Other diseases of anus and rectum |
| K62.0 | Anal polyp |
| K62.1 | Rectal polyp |
| K62.2 | Anal prolapse |
| K62.3 | Rectal prolapse |
| K62.4 | Stenosis of anus and rectum |
| K62.5 | Hemorrhage of anus and rectum |
| K62.6 | Ulcer of anus and rectum |
| K62.7 | Radiation proctitis |
| K62.8 | Other specified diseases of anus and rectum |
| K62.81 | Anal sphincter tear (healed) (nontraumatic) (old) |
| K62.82 | Dysplasia of anus |
| K62.89 | Other specified diseases of anus and rectum |
| K62.9 | Disease of anus and rectum, unspecified |
| K63 | Other diseases of intestine |
| K63.0 | Abscess of intestine |
| K63.1 | Perforation of intestine (nontraumatic) |
| K63.2 | Fistula of intestine |
| K63.3 | Ulcer of intestine |
| K63.4 | Enteroptosis |
| K63.5 | Polyp of colon |
| K63.8 | Other specified diseases of intestine |
| K63.81 | Dieulafoy lesion of intestine |
| K63.89 | Other specified diseases of intestine |
| K63.9 | Disease of intestine, unspecified |
| K64 | Hemorrhoids and perianal venous thrombosis |
| K64.0 | First degree hemorrhoids |
| K64.1 | Second degree hemorrhoids |
| K64.2 | Third degree hemorrhoids |
| K64.3 | Fourth degree hemorrhoids |
| K64.4 | Residual hemorrhoidal skin tags |
| K64.5 | Perianal venous thrombosis |
| K64.8 | Other hemorrhoids |
| K64.9 | Unspecified hemorrhoids |